Prenatal Ultrasound

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Jerry R. Balentine, DO, FACEP

Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

What is prenatal ultrasound?

Like other ultrasound examinations, prenatal or fetal ultrasound uses
high-frequency sound waves to obtain images of the fetus, placenta, and amniotic
sac in a pregnant woman. The test does not involve radiation and is completely
safe for both mother and baby. An ultrasound examination is also known as a
sonogram. The entire procedure can be performed in 30 minutes or less.

Transabdominal ultrasound

Two types of ultrasound exams are used in pregnancy. The most common is a
transabdominal ultrasound, in which the measuring instrument (transducer) is
moved over the surface of the abdomen after a gel has been applied. Sometimes a
full bladder is required to obtain better images, so you may be asked to drink
several glasses of water before the test. There is no pain or discomfort
associated with the test, and it can be performed in the doctor's office.

Transvaginal ultrasound

Transvaginal ultrasound uses a probe that is inserted directly into the
vagina. It is performed in the doctor's office similar to a pelvic examination.
This type of exam is most commonly used in the early weeks of pregnancy to rule
out suspected problems or to assess the gestational age of the embryo. In
early
pregnancy this examination can provide more accurate information then a transabdominal examination.

Why is prenatal ultrasound performed?

As mentioned above, transvaginal ultrasound is most often used in the early
weeks of pregnancy to rule out problems or to determine how far along you are in
the pregnancy. Most pregnant women receive a transabdominal ultrasound around
the 20th week of pregnancy. This exam confirms that the baby is growing normally
and that the placenta is attached normally. The heartbeat of the fetus is
visible, and the movement of the fetus can be observed. Major birth defects can
be visualized by this method, as well. In most cases, it is possible to
determine the sex of the baby through an ultrasound exam at 20 weeks, but this
method is not 100% accurate. You can tell the examiner whether or not you wish
to know the gender of your baby at the time of the examination.

Ultrasound may also be performed earlier or later in the pregnancy for
specific reasons that include:

Determination of multiple gestation

Ensuring the health of the baby and
monitoring its growth

Determining the location of the
placenta

Estimation of gestational age and due
date

Assessing the expected size and weight
of the baby

Determining the amount of amniotic
fluid

Determining the position of the baby

What are 3D and 4D ultrasound?

A 3D ultrasound provides a particularly clear image that resembles a
photograph. A so-called 4D ultrasound provides this image along with a recording
of the baby's movement. Sometimes these ultrasound images are offered by
non-medical providers in stores or other locations. Medical authorities,
including The American College of Obstetricians and Gynecologists and the Food
and Drug Administration do not recommend using these services because the
examiners may not have received proper training and could provide inaccurate
information.

Are there risks associated with prenatal ultrasound?

As mentioned before, there is no radiation exposure during a prenatal
ultrasound. Ultrasound exams have been used for many years, and studies have
never shown any harms associated with the procedure, either on a short- or
long-term basis.